1. Field of the Invention
This invention relates to a method for cleaning a ceramic member for use in a system for producing semiconductors, a cleaning agent and a combination of cleaning agents.
2. Related Art Statement
Recently, an electrostatic chuck has been used for adsorbing and supporting a semiconductor wafer in various processes such as conveying of a wafer, exposure, fine working, cleaning, etching, dicing and film forming such as sputtering and CVD. A ceramic heater for heating a semiconductor wafer and an electrode device for generating a high frequency have been also commercialized.
Recently, a finer wiring rule for a semiconductor has been applied. For example, a fine wiring according to a wiring rule of not larger than 0.13 μm has been applied. Such a finer wiring rule may present a problem of a low level metal contamination, which has not been considered problematic in conventional wiring rules. That is, when a silicon wafer is mounted on a ceramic member and heated at a high temperature, for example, of not lower than 500° C., a trace amount of metal atoms present in the surface region of the ceramic member may be transferred and diffused into the silicon wafer. Such diffusion of the metal atoms may induce semiconductor defects and results in off-specification products.
It has been known to subject a ceramic member to ultrasonic cleaning using an organic solvent and purified water for preventing the metal contamination of the silicon wafer mounted on the member.